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PDM
PDM Operator's Manual Version 2.4a • September 2019
Input Level Meter
PDM’s four color-coded LEDs indicate audio input level at the processor. They’re connected
after the analog-to-digital converter on XLR-equipped PDMs, so they can accurately moni-
tor any input regardless of the
Input
Sensitivity
setting.
n
If all four LEDs are dark, the input signal is below -36 dBFS. This usually represents
normal studio background noise, with no talking or music.
n
As the peak input signal increases between -36 dBFS and Full Scale, successive LEDs
light up.
All four LEDs will light yellow if PDM is expecting a Livewire input but not seeing a valid
signal. This is usually a configuration problem. All four LEDs will also light yellow in the
unlikely event of internal error, even on XLR (analog and AES/EBU) systems.
PDM’s input meter shows instantaneous peaks as a diagnostic aid. It doesn’t display RMS
voltage or time-integrated level, and isn’t a replacement for the sophisticated loudness
meters found in a modern broadcast facility.
Summary of Contents for PDM
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